Such devices, for example DVE (digital voice enhancement) systems, have the task of improving the acoustic communication between users, or the acoustic communication of users with an acoustic interface, such as a voice-recognition system or a handsfree telephone system, in a space. In addition to engine and wind noise, communication may be impeded by overly intense damping of individual, spatial, acoustic transmission routes. To this end, the devices include different microphones and loudspeakers, which are assigned to specific spatial positions. Instead of individual microphones, microphone arrays are also conventional, the microphones of which are aligned with the respective spatial positions.
German Published Patent Application No. 199 38 158 describes a device for compensating for losses of an acoustic signal on a transmission path between at least one transmitting location and least one receiving location in a space, a control unit being provided for determining the transmission path and ascertaining at least one parameter of a corresponding transfer function, and the control unit being connected to at least one level balance or automatic gain control, which, in combination with at least one echo compensator, is positioned between the transmitting location and the receiving location for controlling the acoustic signal level for a specifiable position in the transmission path. In this context, the microphone having the highest signal level is determined by the control unit. In each instance, this microphone represents the active microphone. Its assigned loudspeaker is deactivated. The electrical signals from the active microphone to the active loudspeakers are temporally delayed, so that these are synchronous with respect to the acoustic signal path. In addition, they should be attenuated as a function of the position of the loudspeakers, so that the sum of acoustic and electrical signals yields a predefined sound level at the specific spatial positions.